AGRICULTURAL EDUCATION, ETC 559 



I may conclude with the affirmation that in the Australian 

 boy we have excellent material for raising an educated yeomanry 

 equal, if not superior, to that of any other country. He is finely 

 tempered, easily controlled, endowed with superior natural alert- 

 ness, keen, and with a continuous and well-balanced sense of 

 fairness. 



7.— SOME ASPECTS OF THE NITROGEN QUESTION. 

 By PROFESSOR R. D. WATT, M.A., B.Sc. {Agr.}, University of Sydney. 



There is no problem in the whole realm of agricultural science 

 which has given rise to so much discussion and has been the subject 

 of so much investigation and research as the source of supply and 

 method of absorption of the element nitrogen by plants. The 

 mere mention of the term " Nitrogen question " calls to mind the 

 historic researches of De Saussure and Boussingault, the prolonged 

 controversy between Lietig, on the one hand, and Lewes and Gilbert 

 on the other, the illuminating discovery of Hellriegel and Wilfarth 

 and all the later developments with which are associated, amongst 

 others, the names of Warrington and Winogradski, Beyerinck, 

 Ashby and Hall, and, more recently, Russell and Hutchinson. 



To each of these we are indebted for some new light on the 

 subject, either of the original somce or the modes of absorption of 

 the plants' nitrogenous food material. There are, however, still 

 many obscure points connected with the problem which require 

 elucidation. Anyone who has had the experience of studying 

 crop results in conjunction with soil analysis in a moist and tempe- 

 rate climate like that of the British Isles, and also in a semi-tropical 

 and semi-arid country such as the High Veld of the Transvaal, or 

 the wheat fields of Australia, must have been confronted with 

 puzzling anomalies, especially with regard to the nitrogen question. 



People nowadays are inclined to belittle the value of the 

 chemical analysis of soils, but, as far as my experience goes, the 

 percentage of nitrogen in a soil has proved a fairly reliable guide 

 as to the necessity or otherwise for nitrogenous manming, when due 

 allowance has been made for climatic conditions, for the nature of 

 the crop and for the physical character of the soil. Thus, I think, 

 it may be taken for granted that in Great Britain a clay loam or 

 clay soil which contains less than 0.1 per cent, of nitrogen will 

 respond to nitrogenous manuring in the case of both, cereals and 

 root crops. The results obtained from the historic wheat plots 

 on the Broadbalk field at Rothamsted may be regarded as typical. 



The soil on this field is a clay loam containing 0.099 per cent, 

 of nitrogen, and the following figures give the average yield of 



